Cy and Cathy Westcott, 14 year old twins, are the central figures in a very worth while and readable scientific fiction piece of a more realistic nature than the general run. From a mundane (or so Cy thinks) life in Midvale where their father teaches moon astronomy at the university, the twins are suddenly transported to the Nevada mountains for the summer where Dr. Westcott will, work on a private project at Mount Hawthorne Observatory. Cy is intrigued but even in Nevada, his main problem persists: he is unable to get enthusiastic about anything and can only envy those who are. But as the kids are let in on observatory doings and glimpse their real fascination, the scientist's thrill of possible discovery sets Cy alight. When an actual fire rages and threatens to destroy Dr. Westcott's photographs of a second sateilite, Cy rescues the pictures in a gesture that starts him on his own career.